PEBC MCQ Neurology & Mental Health question: weeks with a partial response

PEBC MCQNeurology & Mental Health

A prescription for citalopram 40 mg daily is received for EH, 72, with major depression who has been on 20 mg daily for 6 weeks with a partial response. Her ECG and electrolytes are normal. Which of the following should the pharmacist recommend?

a. Keep citalopram at 20 mg, the maximum over age 65, and try another strategy
b. Dispense 40 mg and repeat the ECG in 6 months
c. Increase gradually to 60 mg for a full response
d. Dispense 40 mg as written, since her baseline ECG is normal

Show the answer and explanation

Answer: a. Keep citalopram at 20 mg, the maximum over age 65, and try another strategy

Because citalopram causes dose-dependent QT prolongation, Health Canada limits the maximum dose to 20 mg daily in patients over 65 (and 40 mg in younger adults). For a partial response in EH, options include optimising other factors, switching to another antidepressant or augmenting, rather than exceeding the age-based maximum; a normal baseline ECG does not remove the dose limit. Source: Health Canada, Celexa (citalopram) and QT prolongation advisory (2012); citalopram product monograph, Dosage: elderly (DPD, checked 2026); CANMAT 2023 MDD update (Lam RW et al. Can J Psychiatry 2024;69:641).

Common mistake

Exceeding the 20 mg citalopram limit in adults over 65.

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